In a conventional image forming apparatus, a drum and process means actable on the drum are unified into a cartridge which is detachably mountable to a main assembly of the apparatus (cartridge type).
With such a cartridge type, maintenance operations for the image forming apparatus can be performed in effect by the user without relying on a service person, and therefore, the operationality can be remarkably improved. Therefore, the process cartridge type is widely used in the field of the image forming apparatus.